Novel Crystal Forms of Quinacridones Made from 2,9-Dimethoxyquinacridone and 2,9-Dichloroquinacridone

ABSTRACT

Novel crystal forms of solid solutions of 2,9-dimethyoxyquinacridone and 2,9-dichloroquinacridone. The crystal forms may be formed by a process comprising the steps of: a) heating a mixture of 2,5-di(4-methoxyanilino)terephthalic acid, and 2,5-di(4-chloroanilino)terephthalic acid in polyphorsphoric acid at a temperature less than 1050 C to form a mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone; b) combining the mixture of 2,9-dimethoxyquinacridone and 2,9-dichloro-quinacridone with water; and c) heating the mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone at a temperature not more than 110° C. Another crystal form may be formed by the process of heating a mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone in a polar aprotic solvent. These products are may be used for coloring fibers, plastics, paints, coatings, printing inks, color filters, cosmetics, automotive coatings, textiles, fibers, powder coatings, in-mold coatings, laminate films, and the like.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application hereby claims the benefit of the provisionalpatent application Ser. No. 61/047,800, filed on Apr. 25, 2008, thedisclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

Quinacridones are well known organic pigments. They may be manufacturedby acid catalyzed ring closure of aniline-terephthalic acids. The colorand other properties of quinacridone pigments are determined by theirsubstitution and crystal structure. Another well known form that affectscolor and other properties is the forming of solid solutions. One suchquinacridone solid solution is formed from the mixture of2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone, which is knownas Color Index Pigment Violet 55. Examples of solid solutions formedfrom different ratios of 2,9-dimethoxyquinacridone and2,9-dichloroquinacridone are shown in U.S. Pat. No. 5,236,498.

Impurities produced during the synthesis of quinacridones also affectthe properties of the final pigment and reduce the amount of pigmentproduced.

Consequently, a need exists for new quinacridone pigments that have anextended range of colors that can be produced with a minimum ofimpurities and have the desired chroma, hue, bleed resistance anddurability.

BRIEF SUMMARY

The above-noted and other deficiencies may be overcome by the newcrystal forms of a solid solution of 2,9-dimethyoxyquinacridone and2,9-dichloroquinacridone, described as Type II and III, and theprocesses for producing them.

In one aspect, a pigment comprising 2,9-dimethoxyquinacridone and2,9-dichloroquinacridone, is made by the process comprising the stepsof: a) heating a mixture of 2,5-di(4-methoxyanilino)terephthalic acid,and 2,5-di(4-chloroanilino)terephthalic acid in polyphorsphoric acid ata temperature less than 105° C. to form a mixture of2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone; b) combining themixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone withwater; and c) heating the mixture of 2,9-dimethoxyquinacridone and2,9-dichloroquinacridone at a temperature not more than 110° C.

In another aspect, a pigment comprising 2,9-dimethoxyquinacridone and2,9-dichloroquinacridone, is made by the process of heating the mixtureof 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone in a polaraprotic solvent.

These and other objects and advantages shall be made apparent from theaccompanying drawings and the description thereof.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments, and together withthe general description given above, and the detailed description of theembodiments given below, serve to explain the principles of the presentdisclosure.

FIG. 1 is the powder X-ray diffraction pattern of the produce in Example1.

FIG. 2 is the powder X-ray diffraction pattern of the produce in Example2.

FIG. 3 is the powder X-ray diffraction pattern of the produce in Example3.

FIG. 4 is the powder X-ray diffraction pattern of the produce in Example4.

FIG. 5 is the powder X-ray diffraction pattern of the produce in Example5.

FIG. 6 is the powder X-ray diffraction pattern of the produce in Example6.

FIG. 7 is the powder X-ray diffraction pattern of the produce in Example7.

FIG. 8 is the powder X-ray diffraction pattern of the produce in Example8.

FIG. 9 is the powder X-ray diffraction pattern of a 50:50 mixture of2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone that is a mixtureof crystal Type I and II.

FIG. 10 is the powder X-ray diffraction pattern of a 90:10 mixture of2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone that is a mixtureof crystal Type I and III.

FIG. 11 is the powder X-ray diffraction pattern of a 10:90 mixture of2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone that is a mixtureof crystal Type III.

DETAILED DESCRIPTION

New crystal forms of solid solutions formed from mixtures of2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone have beenprepared and identified. These crystal forms of solid solutions arecharacterized by different X-ray patterns. The previously known crystalform will be referred to as Type I. The two new crystal forms will bereferred to as Type II and Type III. The crystal structure ofquinacridones is known to be sensitive to many process variables. Suchvariables include the solvent used to precipitate the quinacridone, theimpurities in the reaction, the ring closure reaction conditions and/orconditioning methods.

When these new crystal types were first formed, the new colors of thepigments were originally thought to be because of the differing ratiosof 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone. It was laterdetermined that the new colors are attributable to the new crystaltypes. Some of the new colors are similar to the colors formed by PV19.However, the mixtures of 2,9-dimethoxyquinacridone and2,9-dichloroquinacridone in the new crystal types are able to form amuch larger gamut of colors than PV19.

Type II Crystal Form

In one embodiment, the Type II crystal is formed by ring closing2,5-di(4-methoxyanilino)terephthalic acid, and2,5-di(4-chloroanilino)terephthalic acid in acid at an elevatedtemperature to form a mixture of 2,9-dimethoxyquinacridone and2,9-dichloroquinacridone. This reaction mixture is then added to waterand heated.

Ring closures to form quinacridones may use a variety of acids, such assulfuric acid or polyphosphoric acid. The use of polyphosphoric acid hasthe advantages of being a straightforward and commercially viableprocedure. However, the polyphosphoric acid can produce undesirablebyproducts when the ring closures are done at too high a temperature orfor too long. Controlling the temperature and time of these ringclosures is essential to producing a product that is essentially free ofundesirable byproducts such as phosphated products. The temperature forthe ring closure may be less than 105° C., about 100° C. or less, fromabout 100° C. to about 90° C., or from about 95° C. to about 90° C. Thetemperature need only be high enough to allow the ring closure reactionto take place and for the solvent to have a low enough viscosity. Theamount of polyphosphoric acid used in the ring closing may be from about2 parts by weight to about 50 parts by weight for 1 part by weight ofthe terephthalic acids. In one embodiment the range may be from about 4to about 6 parts of acid to 1 part of the terephthalic acids.

When ring closure is completed, the reaction mixture is added to water,causing the quinacridone to precipitate. The temperature of the watermay be about room temperature. The mixture may be heated and held at atemperature greater than about 80° C., about 85° C., about 90° C., orabout 95° C.

After the ring closure is completed and the reaction mixture quenched,the pigment may be isolated from the slurry by filtration to form apresscake. In one embodiment, the presscake may be reslurried in water.In one embodiment, the pH of the water may then be adjusted to about 12or more by adding a base, then heated. The slurry may be heated and heldat a temperature greater than about 80° C., about 85° C., about 90° C.,about 95° C., about 100° C., about 125° C. or about 135° C. The slurrymay be heated at atmospheric conditions to remove any undesired alkalinesoluble impurities such as partially reacted starting material. Afterthe slurry is cooled, the pigment may be isolated by filtration. Thepresscake may be washed with hot water and de-ionized water.

In one embodiment, the pigment of crystal form Type II, in an automotivesolvent basecoat/clearcoat paint system, has CIE color coordinates ofabout 8.0≦a*≦about 33.0, about −32.1≦b*≦about −12.1, and about19.0≦C*≦about 41.0. In another embodiment, the pigment of crystal formType II, in an automotive solvent basecoat/clearcoat paint system, hasCIE color coordinates of about 10.0≦a*≦about 31.0, about −25.0≦b*≦about−17.0, and about 22.0≦C*≦about 39.0.

In one embodiment, the pigment with crystal Type II comprises from about10% to about 90% 2,9-dimethoxyquinacridone and from about 90% to about10% 2,9-dichloroquinacridone. In another embodiment, the pigment withcrystal Type II comprises from about 25% to about 75%2,9-dimethoxyquinacridone and from about 75% to about 25%2,9-dichloroquinacridone. In another embodiment, the pigment withcrystal Type II comprises from about 25% to about 50%2,9-dimethoxyquinacridone and from about 75% to about 50%2,9-dichloroquinacridone. In another embodiment, the pigment withcrystal Type II comprises about 25% 2,9-dimethoxyquinacridone and about75% 2,9-dichloroquinacridone.

In one embodiment, the pigment is a mixture of crystal Type I and TypeII, and comprises from about 10% to about 90% 2,9-dimethoxyquinacridoneand from about 90% to about 10% 2,9-dichloroquinacridone. In anotherembodiment, the pigment is a mixture of crystal Type I and Type II, andcomprises from about 25% to about 75% 2,9-dimethoxyquinacridone and fromabout 75% to about 25% 2,9-dichloroquinacridone. In another embodiment,the pigment is a mixture of crystal Type I and Type II, and comprisesfrom about 25% to about 50% 2,9-dimethoxyquinacridone and from about 75%to about 50% 2,9-dichloroquinacridone. In another embodiment, thepigment is a mixture of crystal Type I and Type II, and comprises about25% 2,9-dimethoxyquinacridone and about 75% 2,9-dichloroquinacridone.

In one embodiment the pigment has X-ray powder diffraction d-values atabout 3.4 Å, about 4.2 Å, about 6.4 Å, about 8.3 Å, and about 16.7 Å.

In one embodiment, pure crystal Type II may not be formed. Mixtures ofcrystal Type I and II may be formed. Evidence of crystal Type II may beobserved in the X-ray powder diffraction pattern by subtracting thespectra of a Type I sample from the spectra of the mixed sample. The2-theta values not in common with both spectra can be attributed tocrystal Type II.

Type III Crystal Form

In one embodiment the Type III crystal is formed by heating a mixture of2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone in an excess ofpolar aprotic solvent, where the pH of the mixture has been adjusted. Inone embodiment the polar aprotic solvent is N-methyl pyrrolidone. Themixture may be heated to a temperature of not less than about 120° C. Inone embodiment, the mixture may be heated to a temperature of not lessthan about 145° C. In one embodiment, the pH of the mixture in the polaraprotic solvent is not less than about 12. The selected solvent, theselection of heating temperature, and the pH of the mixture may becombined in any way.

In one embodiment the pigment having a crystal form Type III, in anautomotive solvent basecoat/clearcoat paint system, has CIE colorcoordinates of about 7.1≦a*≦about 23.1, about −28.1≦b*≦about −12.7, andabout 19.0≦C*≦about 35.0. In another embodiment, the pigment having acrystal form Type III, in an automotive solvent basecoat/clearcoat paintsystem, has CIE color coordinates of about 13.0≦a*≦about 21.0, about−26.0≦b*≦about −18.0, and about 22.0≦C*≦about 33.0.

In one embodiment, the pigment with crystal Type III comprises fromabout 10% to about 90% 2,9-dimethoxyquinacridone and from about 90% toabout 10% 2,9-dichloroquinacridone. In another embodiment, the pigmentwith crystal Type III comprises from about 25% to about 75%2,9-dimethoxyquinacridone and from about 75% to about 25%2,9-dichloroquinacridone. In another embodiment, the pigment withcrystal Type III comprises from about 25% to about 50%2,9-dimethoxyquinacridone and from about 75% to about 50%2,9-dichloroquinacridone. In another embodiment, the pigment withcrystal Type III comprises about 25% 2,9-dimethoxyquinacridone and about75% 2,9-dichloroquinacridone.

In one embodiment, the pigment is a mixture of crystal Type I and TypeIII, and comprises from about 10% to about 90% 2,9-dimethoxyquinacridoneand from about 90% to about 10% 2,9-dichloroquinacridone. In anotherembodiment, the pigment is a mixture of crystal Type I and Type III, andcomprises from about 25% to about 75% 2,9-dimethoxyquinacridone and fromabout 75% to about 25% 2,9-dichloroquinacridone. In another embodiment,the pigment is a mixture of crystal Type I and Type III, and comprisesfrom about 25% to about 50% 2,9-dimethoxyquinacridone and from about 75%to about 50% 2,9-dichloroquinacridone. In another embodiment, thepigment is a mixture of crystal Type I and Type III, and comprises about25% 2,9-dimethoxyquinacridone and about 75% 2,9-dichloroquinacridone.

In one embodiment the pigment comprises X-ray powder diffractiond-values at about 3.2 Å, about 3.3 Å, about 3.5 Å, about 3.9 Å, about4.1 A, about 4.4 Å, about 5.1 Å, about 5.6 Å, about 5.9 Å, about 8.8 Å,about 17.5 Å.

In one embodiment the pigment comprises from about 25% of2,9-dimethoxyquinacridone and from about 75% of2,9-dichloroquinacridone.

In one embodiment the pigment has X-ray powder diffraction d-values atabout 3.2 Å, about 3.8 Å, about 3.9 Å, about 5.4 Å, about 5.6 Å, about5.9 Å, and about 17.1 Å.

In one embodiment, pure crystal Type III may not be formed. Mixtures ofcrystal Type I and III may be formed. Evidence of crystal Type III maybe observed in the X-ray powder diffraction pattern by subtracting thespectra of a Type I sample from the spectra of the mixed sample. The2-theta values not in common with both spectra can be attributed tocrystal Type III.

These embodiments are only examples of some of the solid solutions thatcan be formed from ring closing 2,9-dimethoxyquinacridone and2,9-dichloroquinacridone by those skilled in the art and are not limitedto the ratios described.

In one embodiment mixtures of crystal Type II and III may be formed byheating a crystal Type II mixture of 2,9-dimethoxyquinacridone and2,9-dichloroquinacridone in an excess of polar aprotic solvent, such asN-methyl pyrrolidone, where the pH of the mixture has been adjusted. Themixture may be heated to a temperature of not less than about 120° C. Inone embodiment, the mixture may be heated to a temperature of not lessthan about 145° C. In one embodiment, the pH of the mixture in the polaraprotic solvent is not less than about 12. The selected solvent, theselection of heating temperature, and the pH of the mixture may becombined in any way.

Characterizations of Type I, II and III crystal phases were performed byX-ray powder diffraction. The X-ray powder diffraction patterns wereobtained by using a Siemens D5000 diffractometer withgraphite-monochromated Cu Kα₁ radiation (λ=1.5406 Å). The instrument wascalibrated by using a quartz standard from Bruker AXS, Inc. (P/NC72298A227B36). The X-ray diffractions peaks are understood to be withinexperimental bounds and can result in slightly different peaks. It isalso understood that other test methods could produce different peaks.

TABLE 1 X-ray Data of Type I-Example 1 d (in angstroms) Intensity 17.4very strong 8.7 medium 6.4 weak 5.8 strong 5.3 weak 4.4 weak, shoulder4.2 weak 3.8 medium 3.5 weak 3.3 very strong

TABLE 2 X-ray Data of Type II-Example 2 d (in angstroms) Intensity 16.7very strong 8.3 weak 6.4 strong 4.2 weak 3.4 medium, broad

TABLE 3 X-ray Data of Type III-Example 3 d (in angstroms) Intensity 17.5strong 8.8 weak 5.9 weak 5.6 very strong 5.1 weak 4.4 weak 4.1 weak 3.9weak 3.5 weak 3.3 medium 3.2 Medium

TABLE 4 X-ray Data of Type III-Example 7 d (in angstroms) Intensity 17.1very strong 8.8 very weak 8.4 very weak 5.9 strong 5.6 medium 5.4 medium5.1 very weak 4.6 weak 4.4 very weak 4.2 weak 4.1 weak 3.9 medium 3.8medium 3.6 weak 3.5 weak 3.3 weak 3.2 very strong 3.1 weak 2.9 weak 2.8very weak 2.7 very weak 2.6 very weak 2.5 very weak, broad 2.4 very weak2.3 weak 2.2 very weak

These two new crystal forms, may be used either alone, mixed, or mixedwith crystal form Type I. Uses include, but are not limited topigmentation of fibers, plastics, paints, coatings, printing inks, colorfilters, cosmetics, automotive coatings, textiles, fibers, powdercoatings, in-mold coatings, laminate films, and the like.

Another application for the solid solutions of 2,9-dimethoxyquinacridoneand 2,9-dichloroquinacridone in the two new crystal forms is for use inFDA-compliant coatings. An FDA-compliant coating is a material such as acured ink film, coating, plastic, or other material substantially freeof solvent extractable materials (i.e., less than 10 ppb, 25 ppb, 50ppb) or residual components when subjected to solvent under a solventextraction test. Other possible uses for the present invention includeany application where low extractable coatings or materials areadvantageous (such as those used in packaging films and materials, foodpackaging films and materials, plastic films, children's toys, textiles,carpet fibers, cosmetics, etc.).

While the present disclosure has illustrated by description severalembodiments and while the illustrative embodiments have been describedin considerable detail, it is not the intention of the applicant torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications may readily appear tothose skilled in the art.

EXAMPLES

The pigments produced in the examples below were evaluated for theircolor properties in an automotive solvent borne basecoat/solvent borneclearcoat system as follows: The dry pigments were dispersed into thesolvent borne basecoat, along with proprietary additives, on a Skandexpaint shaker for 3 hours, using 2 mm steel beads (6:1 pigment: beads).The dispersion was then formulated into paints with either a TiO₂ pasteor an Aluminum paste, to a ratio of 5:95 pigment:TiO₂ (tint) and 50:50pigment: aluminum (metallic). The resulting paints were either drawndownon paper cards (tint) or sprayed onto a coilcoat-primed aluminum panelto a film thickness of 25±5 microns (metallic). The panel was thensprayed with a solvent borne acrylic clearcoat to a total film thicknessof 50±5 microns, and the panel baked again at 260° F. Color data wereobtained using a Macbeth Coloreye 7000A spectrophotometer for the tintdrawdown and an X-Rite MA-68 multi-angle spectrophotometer for thesprayed aluminum panel

Example 1 Type I

A resin flask was charged with 24 parts of 117% polyphosphoric acid. andheated to 110° C. One part of dichloro dianilinoterephthalic acid(DCDATA) was added at a rate that maintained the reaction at 110-115° C.After addition of the DCDATA, the reaction was heated to 120° C. andheld at 120° C. for 30 minutes. The mixture was then cooled to 85° C.and 3 parts of dimethoxy dianilinoterephthalic acid (DMATA) was added ata rate to maintain the reaction at 85-90° C. during the addition. Afterthe DMATA was added, the mixture was held at 100-105° C. for 3 hours.The mixture was then added to a stirred round bottom flask containing42.5 parts methanol at room temperature. During the addition, themethanol was cooled to keep the temperature at 60° C. or below. Afterthe addition was complete, the resulting slurry was heated to reflux andmaintained at reflux for 1 hour. The slurry was cooled to 40° C.,isolated by filtration on a Buchner funnel, and washed to a pH>3.0. Thewashed presscake was reslurried in water, the pH adjusted to 6.5 to 7.5,and 0.3 parts 50% caustic soda was added. The slurry was then added to aParr pressure reactor, heated to 140° C. and held at 140° C. for 1 hour.After cooling, the product was isolated by filtration on a Buchnerfunnel, washed alkali free with water, and dried. The powder x-raydiffraction pattern was the same as the previously described crystalform (U.S. Pat. No. 5,236,498, see FIG. 1), which herein is identifiedas Type I.

Example 2 Type II

A resin flask was charged with 20 parts of 117% polyphosphoric acid, andheated to 90° C. One part of dichloro dianilinoterephthalic acid(DCDATA) was added at a rate that maintained the reaction at 90-95° C.After addition of the DCDATA, 3 parts of dimethoxy dianilinoterephthalicacid (DMATA) was added at a rate to maintain 90-95° C. during theaddition. After the DMATA was added, the reaction mass was held at90-95° C. for 6 hours. The reaction mass was then added slowly to 153parts of agitated water at room temperature. After the addition wascomplete, the resulting slurry was heated to 90° C. and held at 90° C.for 1 hour. The product was isolated from the slurry by filtration on aBuchner funnel, and washed with water. The presscake was reslurried in153 parts water, adjusted to a pH>12 with 50% caustic soda, and heatedto 90° C. for 1 hour. After cooling, the product was isolated byfiltration on a Buchner funnel, washed with hot water, then de-ionizedwater to a conductivity <100 μs. After drying, the powder x-raydiffraction pattern was distinctly different from that of the Type Icrystal (Example 1), indicating a new crystal form (see FIG. 2), hereinidentified as Type II.

Pigments containing at least the new crystal form Type II were also madefrom 10% DCDATA and 90% DMATA; 90% DCDATA and 10% DMATA; 50% DCDATA and50% DMATA; and 75% DCDATA and 25% DMATA.

Example 3 Type III

A resin flask was charged with 24 parts of 117% polyphosphoric acid, andheated to 90° C. One part of dichloro dianilinoterephthalic acid(DCDATA) was added at a rate that maintains the mixture at 90-95° C.After addition of the DCDATA, 3 parts of dimethoxy dianilinoterephthalicacid (DMATA) was added at a rate to maintain 90-95° C. After the DMATAwas added, the reaction mass was heated to 100° C. and held at 100-105°C. for 6 hours. The mixture was then added slowly to 150 parts ofagitated water at room temperature. After the addition was complete, theresulting slurry was heated to 90° C. and held at 90° C. for 1 hour. Theproduct was isolated by filtration on a Buchner funnel and washed to apH>3.0 with water. The presscake was reslurried in 15 parts N-methylpyrrolidone, adjusted to pH 12.0 to 12.2 with 50% caustic soda andcharged into a Parr pressure reactor. The reactor was heated to 125° C.and held at 125° C. for 3 hours. After cooling, the slurry was isolatedby filtration on a Buchner funnel, washed until alkali free, and dried.The powder x-ray diffraction pattern of the product is distinctlydifferent from both the Type I and Type II crystals, indicating a thirdcrystal form (see FIG. 3), herein identified as Type III.

Example 4

A resin flask was charged with 24 parts of 117% polyphosphoric acid, andheated to 90° C. One part of dichloro dianilinoterephthalic acid(DCDATA) was added at a rate that maintained the mixture at 90-95° C.After addition of the DCDATA, 3 parts of dimethoxy dianilinoterephthalicacid (DMATA) was added at a rate to maintain 90-95° C. After the DMATAwas added, the reaction mass was heated to 100° C. and held at 100-105°C. for 3 hours. The mixture was then added slowly to 100 parts ofagitated water at 80° C. After the addition was complete, the resultingslurry was heated to 90° C. and held at 90° C. for 1 hour. The productwas isolated from the slurry by filtration on a Buchner funnel, andwashed with water. The presscake was reslurried in 153 parts water,adjusted to pH>12 with 50% caustic soda, and heated to 90° C. for 1hour. After cooling, the product was isolated by filtration on a Buchnerfunnel, washed with hot water until the pH was greater than 3.5. Thepresscake was reslurried with 133 parts water. Rosin (a surfacetreatment) (0.25 parts) was added to the slurry. The slurry was heatedto 80° C. and 0.25 parts calcium chloride dihydrate was added. Thepigment was isolated by filtration and dried at 70° C. Powder x-raydiffraction pattern shows this product to be a very amorphous mixture oftype I and type II crystals with type II being the majority (see FIG.4).

Example 5

A resin flask was charged with 24 parts of 117% polyphosphoric acid, andheated to 90° C. One part of dichloro dianilinoterephthalic acid(DCDATA) was added at a rate that maintained the mixture at 90-95° C.After addition of the DCDATA, 3 parts of dimethoxy dianilinoterephthalicacid (DMATA) was added at a rate to maintain 90-95° C. After the DMATAwas added, the reaction mass was heated to 100° C. and is held at100-105° C. for 3 hours. The mixture was then added slowly to 100 partsof agitated water at room temperature. After the addition was complete,the resulting slurry was heated to 90° C. and held at 90° C. for 1 hour.The product was isolated from the slurry by filtration on a Buchnerfunnel, and washed with water. The presscake was reslurried in 153 partswater, adjusted to a pH>12 with 50% caustic soda, and heated to 90° C.for 1 hour. After cooling, the product was isolated by filtration on aBuchner funnel, washed with hot water until the pH was greater than 3.5.The resulting presscake was reslurried in 133 parts water. The pH of theslurry was adjusted to 12 with 50% caustic soda. This slurry was chargedinto an autoclave and heated for 3 hours at 124° C. The autoclave wascooled to below 80° C. and discharged. The pigment was isolated from theslurry by filtration on a Buchner funnel. The presscake was againreslurried with 133 parts water. Rosin (a surface treatment) (0.25parts) was added to the slurry. The slurry was heated to 80° C. and 0.25parts calcium chloride dihydrate was added. The pigment was isolated byfiltration and dried at 70° C. The crystal type was a mixed crystal oftype I and II comprising more of the type II crystal. This pigment has ahue that is 15.6 units redder and a chroma that is 15.4 units higherthan the pigment of Example 4 (see FIG. 5).

Example 6 Type I and II

A resin flask was charged with 24 parts of 117% polyphosphoric acid, andheated to 90° C. One part of dimethoxy dianilinoterephthalic acid(DMATA) was added at a rate that maintained the mixture at 90-95° C.After addition of the DMATA, 3 parts of dichloro dianilinoterephthalicacid (DCDATA) was added at a rate to maintain 90-95° C. After the DCDATAwas added, the mixture was heated to 100° C. and held at 98-102° C. for4.5 hours. The mixture was then added slowly to agitated water at 55° C.After the addition was complete, the water slurry was heated to 90° C.and held at 90° C. for 1 hour. After cooling, the product was isolatedby filtration on a Buchner funnel, washed with water until the pH wasgreater than 3.5. The resulting presscake was reslurried in water,adjusted to a pH of 12 with 50% caustic soda, then heated to 90° C.After holding the slurry at 90° C. for 1 hour, the slurry was cooled to70° C. or lower. The product was then isolated on a Buchner funnel andwashed until alkali free. Part of the presscake was dried. This productalthough very amorphous is an example of a mixed crystal of type I andII, with type II being dominant (see FIG. 6).

Example 7 Type III

One part alkali presscake from Example 6 was slurried in 6 partsN-methyl pyrrolidone and 0.05 parts of 45% caustic potash was added.This slurry was heated to 145° C. As the temperature approached 145° C.,water was distilled off. The moisture content of the slurry determinesthe temperature that the water vapor starts to distill. The slurry washeld at 145° C. for 3 hours. The product was isolated at 70° or lower ona Buchner funnel. The presscake was washed with water and dried at 70°C. This product was a different crystal form compared to the crystalform obtained in Example 6. There are some variations in peaks and peakintensities but both Examples 7 and 3 are type III crystals (see FIG.7). Example 7 has the reverse ratio of DMATA and DCDATA compared to thatused in Example 3.

Example 8

A resin flask was charged with 24 parts of 117% polyphosphoric acid, andheated to 90° C. One part of dichloro dianilinoterephthalic acid(DCDATA) was added at a rate that maintained the mixture at 90-95° C.After addition of the DCDATA, 3 parts of dimethoxy dianilinoterephthalicacid (DMATA) was added at a rate to maintain 90-95° C. After the DMATAwas added, the mixture was heated to 100° C. and held at 98-102° C. for4.5 hours. The mixture was then to a stirred round bottom flaskcontaining 42.5 parts methanol at room temperature. During the addition,the methanol was cooled to keep the temperature at 60° C. or below. Oncethe addition was complete, the resulting slurry was heated to reflux andmaintained at reflux for 1 hour. The slurry was cooled to 40° C.,isolated by filtration on a Buchner funnel, and washed to a pH>3.0. Thewashed presscake was reslurried in enough methanol to bring thewater/methanol slurry to 80% methanol. Three parts caustic potash 45%was added. The mixture was added to an autoclave and heated underpressure to 130° C. for 3 hours. The reaction was cooled to below theboiling point and removed for filtration. The isolated product was driedat 70° C. The x-ray of the product was a mixture of Type I and Type IIIcrystals with the majority being Type III (see FIG. 8).

Pigments containing at least the new crystal form Type III were alsomade from 10% DCDATA and 90% DMATA (this procedure used 20 parts PPAinstead of 24 parts); and 90% DCDATA and 10% DMATA.

Caustic soda 50% or equivalent flake material may replace the causticpotash 45% in the autoclave. All parts are by weight.

Example 9 Application of Type I and II

Flexible PVC is made incorporating the pigment prepared as in Example 5.

Masstone

Flexible PVC (89.1 g) was added to the rollers and mixed in a commercial2-roll mill set to an operating temperature of 310° F. and the nipsetting at 38 mils. The PVC was mixed until it melted and became clear.Pigment (0.0900 g) was added to the PVC, and blended for 3 minutes. Thecolored PVC sheet was removed from the rollers using a nip of 73 mils.After the sheet was cooled it was added to the rollers of the cold millfor 12 passes, where the sheet was folded during each pass. The sheetwas removed from the cold mill and put back on the hot mill. The nipsetting was 38 mils until the sheet was smooth and uniform. The coloredPVC sheet was then removed from the mill at a nip setting of 73 mils.

Tint

Flexible PVC (58.74 g) and Moltopren White Paste (previously hand mixed)was added to the rollers and mixed in a commercial 2-roll mill set to anoperating temperature of 310° F. and the nip setting at 38 mils. The PVCwas mixed until it melted and became clear. Pigment (0.06 g) was addedto the PVC, and blended for 3 minutes. The colored PVC sheet was removedfrom the rollers using a nip of 25 mils. After the sheet was cooled itwas added to the rollers of the cold mill for 12 passes, where the sheetwas folded during each pass. The sheet was removed from the cold milland put back on the hot mill. The nip setting was 22 mils until thesheet was smooth and uniform. The colored PVC sheet was then removedfrom the mill at a nip setting of 25 mils.

Example 10 Type I and III

A pigment that was ring closed in a process similar to Example 5 butconditioned in an autoclave at 120° C. in an alkaline mixture of waterand methanol with the majority being methanol was incorporated intoflexible PVC using the test method described in Example 9.

Masstone Masstone Tint Tint Sample a* b* a* b* PV 19 beta 20.31 0.0925.56 −20.12 PR 202 38.66 9.37 27.55 −11.2 PV 19 gamma 29.01 6.85 46.20−8.98 Example 9 21.45 −8.49 31.92 −28.79 Example 10 17.73 −7.97 17.25−24.31Color Index Pigment Violet 19 beta and Color Index Pigment Violet 19gamma are unsubstituted quinacridones. The beta crystal is a violet andthe gamma crystal is a red. Color Index Pigment Red 202 is2,9-dichloroquinacridone.

Those skilled in the art having the benefit of the teachings of thepresent invention as hereinabove set forth, can effect numerousmodifications thereto. These modifications are to be construed as beingencompassed within the scope of the present invention as set forth inthe appended claims.

Example 11 Solvent Extractable Test

Preparation of low density polyethylene test plaques. Food grade lowdensity polyethylene (LDPE) from Equistar Chemicals LP, Houston Tex.,was colored with 0.5% pigment and then pressed into rectangular plaquesmeasuring 2.25″×1.75″ and 0.125″ thick. The total surface area of theLDPE is 23.6 square inches. Non colored LDPE plaques were also preparedfor use as blanks and for spike/recovery studies.

Stainless steel rods were used for holding the LDPE plaques at least 5mm apart in the migration vessel. The sample holder was then place in 16oz. wide mouth glass bottle and 250 ml of hot solvent (10% ethanol inwater) was added. The bottle was sealed with a Teflon lined cap. A linewas drawn on the bottle to mark the level of the solvent in the bottleto check for possible loss of gaseous solvent from the extractionvessel. The bottles were then placed in an oven at the appropriatetemperature as required for the specific condition of use.

Four sets of test samples were prepared and the solutions were analyzedafter 2, 24, 96 and 240 hours. The test was conducted to meet theconditions of use B as listed in Appendix II of the USFDA Guidance forIndustry, preparation of FCNs and FAPs for food contact substances:Chemistry Recommendations, Final Guidance, April 2002. The initial 2hours was done at 100° C. The tests after 24, 96 and 240 hours wereconducted at 40° C. The 2, 24 and 96 hour samples were carried out once.The 240 hours (10 day samples) were done in triplicate. Blanks were alsoprepared after each migration test condition.

Validation experiments were performed using LDPE blank solution from the10 day extraction. Each of the solutions were fortified at approximatelyone-half, one, and two times respectively, the average amount ofmigration.

At the end of each extraction time the samples were allowed to cool toroom temperature and the LDPE plaques removed from the migration vessel.The solutions were then evaporated to dryness in a 250-ml beaker. Theresidue was dissolved in 10 mL of Dimethyl Sulfoxide (DMSO). Visiblespectra of the solutions were obtained from 350 to 700 nm. Theabsorbance at the wavelength of maximum absorption (530 nm) wasmeasured. The absorbance of the blank at the same wavelength wassubtracted from the sample absorbance. The final results were correctedfor recovery as determined from the blank solutions fortified with PV55.A calibration curve of the test pigment in DMSO at three levelscorresponding to 5, 10 and 20 ppb (equivalent to 1.20 2.40, and 4.80μg/10 mL) was obtained and the response was found to be linear.

Four samples of Type III crystal that were conditioned for use inplastic were tested according to the above procedure in triplicate andthe results were averaged. Sample A 7.8 ppb, Sample B<5 ppb, Sample C<5ppb, and Sample D 6.3 ppb.

1-13. (canceled)
 14. The pigment of claim 27, made by the process ofheating the mixture of 2,9-dimethoxyquinacridone and2,9-dichloroquinacridone in a polar aprotic solvent, where the pH of themixture has been adjusted.
 15. The pigment of claim 14, where the pH ofthe mixture in the polar aprotic solvent is not less than about
 12. 16.The pigment of claim 14, where the polar aprotic solvent is N-methylpyrrolidone.
 17. The pigment of claim 14, where the2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone is heated to atemperature of not less than about 120° C. 18-19. (canceled)
 20. Thepigment of claim 14, where the pigment in an automotive solventbasecoat/clearcoat paint system has CIE color coordinates of about7.1≦a*≦about 23.1, about −28.1≦b*≦about −12.7, and about 19.0≦C*≦about35.0.
 21. (canceled)
 22. The pigment of claim 14, where the pigmentcomprises from about 10% to about 90% of 2,9-dimethoxyquinacridone andfrom about 90% to about 10% of 2,9-dichloroquinacridone.
 23. (canceled)24. The pigment of claim 14, where the pigment comprises from about 25%to about 75% of 2,9-dimethoxyquinacridone and from about 75% to about25% of 2,9-dichloroquinacridone.
 25. The pigment of claim 14, where thepigment has X-ray powder diffraction d-values at about 3.2 Å, about 3.3Å, about 3.5 Å, about 3.9 Å, about 4.1 Å, about 4.4 Å, about 5.1 Å,about 5.6 Å, about 5.9 Å, about 8.8 Å, about 17.5 Å.
 26. The pigment ofclaim 14, where the pigment has X-ray powder diffraction d-values atabout 3.2 Å, about 3.8 Å, about 3.9 Å, about 5.4 Å, about 5.6 Å, about5.9 Å, and about 17.1 Å.
 27. A pigment comprising2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone, that comprisescrystal form Type III.
 28. The pigment of claim 17, comprising crystalform Type I and III.
 29. A process comprising the step of heating amixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone in apolar aprotic solvent to a temperature of not less than about 120° C.30. The process of claim 29 where the pH of the mixture in the polaraprotic solvent is not less than about
 12. 31. The process of claim 29,where the polar aprotic solvent is N-methyl pyrrolidone.
 32. The pigmentof claim 17, made by the process comprising the steps of: a) heating amixture of 2,5-di(4-methoxyanilino)terephthalic acid, and2,5-di(4-chloroanilino)terephthalic acid in polyphorsphoric acid at atemperature less than 105° C. to form a mixture of2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone; b) combining themixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone withwater; c) heating the mixture of 2,9-dimethoxyquinacridone and2,9-dichloroquinacridone; and d) heating the mixture of2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone in a polaraprotic solvent, where the pH of the mixture has been adjusted.
 33. Thepigment of claim 32, where the pH of the mixture in the polar aproticsolvent is not less than about 12.